That's an early 1928 frame. The front of the motor bolts directly on the frame. You can convert to the Y mount, but you need to cut that top part of the frame off. Good luck. Jeff
That front crossmember is rather rare, as many of the 28's were cut off to reduce vibration. In a doodlebug it should not be a problem. If it were mine, I would leave it alone, and just bolt the engine to it.